The present invention relates to an apparatus for intercepting cleaning bodies used for cleaning a tube-type heat-exchanger.
The apparatus is disposed in a discharge or outlet conduit of the tube-type heat-exchanger for intercepting cleaning bodies such as, for example, balls made of elastic material, mixed in a liquid cooling media such as, for example a cooling water, with the cleaning bodies being passed through a plurality of heat conductive tubes or pipes and being returned to an inlet conduit of the heat-exchanger, whereby the heat-exchanger is continuously cleaned by the recirculating cleaning bodies during operation of the heat-exchanger.
A conventional type of the apparatus for intercepting cleaning bodies is disclosed in FIGS. 16 to 18 of U.S. Pat. No. 3,021,117. The apparatus comprises a conduit, a pair of upstream gratings, a pair of downstream gratings, and a discharge tube with a funnel disposed downstream of the downstream gratings for receiving cleaning bodies from the gratings and taking the cleaning bodies out of the conduit. The apparatus is excellent in that its construction is stable, relatively simple except for the gratings and it can surely intercept the cleaning bodies.
However, the apparatus also has various drawbacks. One of them is that the axial length of the conduit necessary to contain the gratings is large because the upstream and downstream gratings are generally the same in axial length and arranged axially in series. Therefore, the apparatus is large in size, so that the manufacturing transporting, and installation costs are increased. Another drawback is that a large pressure loss takes place when the cooling water flows in the apparatus because of obstruction in the flow of the cooling water, that is, the funnel of the discharge pipe and a throat portion defined by the gratings are disposed in a central portion of the conduit where the cooling water has the largest flow rate.
U.S. Pat. No. 3,021,117 additionally proposes a funnel shaped intercepting device formed of individual rings disposed coaxially in a step-like manner and held together by supporting bars. A disadvantage of this type of the intercepting apparatus is that it is structually weak so that it can not be adapted in a large capacity of apparatus having a conduit diameter more than 1000 mm. In the apparatus, the rings are disposed perpendicularly to a flow direction of a cooling water, and the cooling water flow is disturbed by the rings so that flow resistance is increased.
Another relevant prior art is Japanese utility model publication No. 43-21002 (1968). Wherein an apparatus for intercepting cleaning bodies for a tube-type heat-exchanger, is provided with a pair of ball passages for taking cleaning bodies out of a conduit at the side wall of the conduit. The side wall is necessarily of a complicated construction in order to provide for the pair of ball passages which partially extend along the side wall of the conduit.